1. Field of the Invention
The present invention relates to a toll collection system to collect tolls from vehicles through wireless communication on such toll roads as expressways, an onboard unit that is loaded on vehicles to which this system is applicable and a toll collection method.
2. Description of the Related Art
Generally, as a toll collection system for exactly calculating tolls on toll roads, there is a magnetic card type toll collection system using tickets, prepaid cards, cash cards or currency.
In this magnetic card type toll collection system, a magnetic card recording entrance gate information to specify which entrance gate was used is issued as a ticket at an entrance gate into which a vehicle enters and a vehicle driver carries this ticket. At an exit gate, the entrance gate information recorded on the ticket carried by the driver is read and a toll is calculated. The calculated amount is presented to the driver and the calculated toll is collected in cash, by a pre-paid card, etc.
However, in the case of this magnetic card type toll collection system, what is needed for a driver at the entrance gate of a tollbooth is only to get a ticket from an automatic ticket issuing machine and therefore, there are not many traffic jams in the vicinity of the entrance gate. However, at the exit gate of a tollbooth there are extremely many work intensive tasks such as receiving/issuing of tickets/receipt, collection of tolls. Accordingly, there has been so far such a problem that when the number of vehicles using an expressway increased, the traffic was congested in the vicinity of an exit gate.
So, in an effort to relieve this traffic congestion, an ETC system (Electronic Toll Collection System), that is, a wireless card type toll collection system is being introduced in recent years. This ETC system is to collect a toll using an IC card that is set in an onboard unit through the wireless communication between an onboard unit loaded on a vehicle and a roadside equipment including antennas installed at a tollgate.
In other words, at an entrance gate, a vehicle with an onboard unit loaded (hereinafter, referred to as an ETC vehicle) is controlled so as to store entrance gate information in an IC card that is set in its onboard unit through wireless communication with a roadside equipment installed at the entrance gate. On the other hand, at an exit gate, the entrance information is read from an onboard unit and an IC card of an ETC vehicle through wireless communication with a roadside equipment installed at the exit gate. A toll is automatically calculated based on this read entrance information. As a method to automatically calculate tolls, there are such methods as a method to record a pre-paid amount on an IC card and use this IC card as a pre-paid card; a method to record a contract information to specify user""s deposit account, etc. in advance on an IC card and use this IC card as a credit card, etc.
One should note that, in such ETC systems as this, the writing speed on IC cards is slower than the wireless communication speed and therefore, an onboard unit starts the writing on an IC card after completing the wireless communication process with a roadside equipment.
However, there are such tollgates where a plurality of antennas are installed along the entering direction of vehicles, for instance, a first antenna, a second antenna and so on. In this case, an onboard unit is required to start the writing on an IC card and also the communication with a second antenna after the communication with a first antenna.
If a high efficiency processor (CPU) is loaded into an onboard unit, it becomes possible to execute the write process on IC card in parallel with the communication process with a second antenna but the price of an onboard unit becomes expensive.
Further, the number of antennas that are installed at a tollgate is determined according to the operation but may possibly be changed in the future. As a person substantially controlling an onboard unit is an end-user himself (herself), it is not easy to change the software of an onboard unit and it is necessary to make an arrangement to be able to cope with the wireless communication flexibly regardless of the number of antennas.
It is an object of the present invention to provide a toll collection system, an onboard unit and a toll collection method that are capable of flexibly coping with the toll collection without changing the functions of an onboard unit regardless of the number of antennas that are installed at a tollgate.
According to the present invention, a toll collection system is provided which to collect a toll through wireless communication between an onboard unit carried by a vehicle, stacking an IC card and a gate equipment installed at a tollgate. The system comprises: said gate equipment including: wireless communication means for performing the wireless communication with said onboard unit; and notification means for sending a notification information showing the presence of, the number of or time until arrival at wireless communication means installed along the proceeding direction of a vehicle to said onboard unit through said wireless communication means; and said onboard unit including: means for writing data sent from said wireless communication means onto said. IC card after executing the communication process with all of the wireless communication means based on said notification information.
Further, according to the present invention, an onboard unit capable of being carried by a vehicle and which performs wireless communication with a tollgate showing data of the passing through of vehicles through a wireless communication means installed at the tollgate is provided. The onboard unit comprises receiving means for receiving notification information showing the presence of, the number of or time until arrival at wireless communication means installed at the latter stage along the proceeding direction of said vehicle; and means for writing data sent from said wireless communication means onto an IC card stacked in said onboard unit after executing the communication process with all of said wireless communication means based on said notification information received by said receiving means.
Further, according to the present invention, a method is provided to collect a toll through the wireless communication between the onboard unit carried by a vehicle, stacking an IC card and a gate equipment installed at a tollgate. This method comprises sending notification information showing the presence or the number of wireless communication means installed at the latter stage from said gate equipment to said onboard unit through wireless communication means; and said onboard unit starting writing process to an IC card after executing the communication process with all of the wireless communication means of said gate equipment based on said notification information.